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Recent Experience With RF "Modem-ish" Data Links ?

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  Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-05-25 01:46 -0400
    Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-05-25 17:56 +0000
      Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-05-26 01:27 -0400
        Re: Recent Experience With RF "Modem-ish" Data Links ? TheLastSysop <thelastsysop@dev.null> - 2026-05-26 22:11 +0000
          Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-05-26 23:04 -0400
            Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-05-27 03:21 +0000
              Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-05-27 00:18 -0400
                Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-05-27 07:09 +0000
                  Re: Recent Experience With RF "Modem-ish" Data Links ? Nuno Silva <nunojsilva@invalid.invalid> - 2026-06-04 17:40 +0100
                    Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-04 14:43 -0400
                      Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-06-04 23:09 +0000
                        Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-04 23:14 -0400
                          Need for new personal ID numbers Lars Poulsen <lars@beagle-ears.com> - 2026-06-04 20:46 -0700
                            Re: Need for new personal ID numbers c186282 <c186282@nnada.net> - 2026-06-05 01:29 -0400
                          Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-06-05 04:53 +0000
                            Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-05 02:13 -0400
                          Re: Recent Experience With RF "Modem-ish" Data Links ? Andy Burns <usenet@andyburns.uk> - 2026-06-05 09:26 +0100
                            Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-05 05:24 -0400
                            Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-06-05 17:36 +0000
                              Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-06 00:16 -0400
                                Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-06-06 06:08 +0000
                                  Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-06 02:43 -0400
                                    Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-06-06 20:19 +0000
                                      Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-07 05:54 -0400
                                        Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-06-07 19:43 +0000
              Re: Recent Experience With RF "Modem-ish" Data Links ? The Natural Philosopher <tnp@invalid.invalid> - 2026-05-27 14:14 +0100
        WiFi range ... Lars Poulsen <lars@beagle-ears.com> - 2026-05-31 21:19 -0700
          Re: WiFi range ... TheLastSysop <thelastsysop@dev.null> - 2026-06-01 04:26 +0000
            Re: WiFi range ... Lars Poulsen <lars@beagle-ears.com> - 2026-06-01 22:44 -0700
          Re: WiFi range ... Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-07-31 23:00 +0000
            Re: WiFi range ... c186282 <c186282@nnada.net> - 2026-07-31 23:34 -0400
              Re: WiFi range ... rbowman <bowman@montana.com> - 2026-08-01 05:15 +0000
                Re: WiFi range ... c186282 <c186282@nnada.net> - 2026-08-01 21:30 -0400
                  Re: WiFi range ... rbowman <bowman@montana.com> - 2026-08-02 04:13 +0000
                    Re: WiFi range ... c186282 <c186282@nnada.net> - 2026-08-02 01:23 -0400
                  Re: WiFi range ... "Carlos E. R." <robin_listas@es.invalid> - 2026-08-02 14:26 +0200
                    Re: WiFi range ... The Natural Philosopher <tnp@invalid.invalid> - 2026-08-02 15:00 +0100
                      Re: WiFi range ... rbowman <bowman@montana.com> - 2026-08-02 19:46 +0000
                    Re: WiFi range ... c186282 <c186282@nnada.net> - 2026-08-02 22:57 -0400
                  Re: WiFi range ... Robert Komar <robk@robpc4.robk-home.org> - 2026-08-02 11:59 -0400
                    Re: WiFi range ... rbowman <bowman@montana.com> - 2026-08-02 19:44 +0000
                    Re: WiFi range ... c186282 <c186282@nnada.net> - 2026-08-03 00:12 -0400
                      Re: WiFi range ... The Natural Philosopher <tnp@invalid.invalid> - 2026-08-03 12:22 +0100
                        Re: WiFi range ... c186282 <c186282@nnada.net> - 2026-08-03 20:20 -0400
                          Re: WiFi range ... The Natural Philosopher <tnp@invalid.invalid> - 2026-08-04 11:37 +0100
                            Re: WiFi range ... c186282 <c186282@nnada.net> - 2026-08-05 01:52 -0400
                              Re: WiFi range ... The Natural Philosopher <tnp@invalid.invalid> - 2026-08-05 13:21 +0100
                                Re: WiFi range ... c186282 <c186282@nnada.net> - 2026-08-06 02:47 -0400
                                  Re: WiFi range ... The Natural Philosopher <tnp@invalid.invalid> - 2026-08-06 13:01 +0100
                                    Re: WiFi range ... rbowman <bowman@montana.com> - 2026-08-06 19:56 +0000
                                      Re: WiFi range ... The Natural Philosopher <tnp@invalid.invalid> - 2026-08-06 22:15 +0100
                                        Re: WiFi range ... rbowman <bowman@montana.com> - 2026-08-07 03:41 +0000
                                          Re: WiFi range ... The Natural Philosopher <tnp@invalid.invalid> - 2026-08-07 12:26 +0100
                                  Re: WiFi range ... rbowman <bowman@montana.com> - 2026-08-06 19:33 +0000
        Re: Recent Experience With RF "Modem-ish" Data Links ? Andy Burns <usenet@andyburns.uk> - 2026-06-01 08:10 +0100
          Re: Recent Experience With RF "Modem-ish" Data Links ? TheLastSysop <thelastsysop@dev.null> - 2026-06-01 07:33 +0000
            Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-02 01:35 -0400
          Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-02 01:15 -0400
            Re: Recent Experience With RF "Modem-ish" Data Links ? Lars Poulsen <lars@beagle-ears.com> - 2026-06-01 22:50 -0700
              Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-06-02 03:04 -0400

Page 3 of 3 — ← Prev page 1 2 [3]

#89476 — Re: WiFi range ...

On Sun, 2 Aug 2026 11:59:29 -0400, Robert Komar wrote:

> Back when I was an student in the 80's, one mechanical engineering
> professor described doing wet/dry bulb measurements.  The thermometers
> were tied to lanyards, and you would whirl them around in the air at a
> certain rate to get more air flow over the bulbs during the measurement.
> It increased the difference between the wet and dry readings for better
> accuracy, and the tables were adjusted for that affect.  My old
> thermodynamics textbook has a Psychrometric Chart in the back that you
> could use for calculating the absolute humidity from the temperatures. 
> It doesn't say whether the bulbs should be whirled around or not, maybe
> that was common knowledge back then.

https://ktagage.com/product/sling-psychrometer/

The video shows the use of the charts. Barometric pressure comes into play 
too. I assume that takes into account elevation. The side by side types 
probably are good enough although with no motion the air around the wet 
bulb will be affected by the evaporation.

Digital hygrometers measure the capacitance or resistance of a moisture 
sensitive material. The common DHT11 uses resistance which isn't as 
accurate as capacitance but what do you want for $3? One of the Accurite 
pages mentions both methods but doesn't say which is used. In both cases 
onboard processing handles the raw measurements of the thermistor and 
humidity sensor 

I suppose I could build a 70 cm Yagi and go fox hunting to find the 
Accurite unit but whoever owns it probably wouldn't be happy with me 
taking it apart.

[toc] | [prev] | [next] | [standalone]

#89494 — Re: WiFi range ...

On 8/2/26 11:59, Robert Komar wrote:
> c186282 <c186282@nnada.net> wrote:
>>
>>    Now you CAN make a wet/dry-bulb unit using two DS
>>    18b20 temperature sensors - one kinda wrapped in a
>>    light wet cloth. Suggest dipping both sensors in epoxy
>>    to enhance water resistance. DO adjust the reported
>>    temperatures, dry, to be the same. The Dallas 1-wire
>>    devices are GOOD, but no two of them will read
>>    EXACTLY the same. Calibrate at the bench, using a
>>    scientific conventional thermometer as reference.
>>
>>    Now the wet bulb, how the hell do you KEEP it wet ?
>>    This can be a PROBLEM depending on environment. Where
>>    I was, there was surely a little rain every 7-10 days.
>>    A cheepo reservoir was easy to rig. It's also possible
>>    to lace the wet cloth with a chemical, ammonium nitrate
>>    for example, which is extremely hydroscopic - but the
>>    chosen salt WILL affect the reading and compensation
>>    will be needed.
>>
>>    Anyway, wet+dry will give you a very real figure, but
>>    at added complexity.
>>
>>    Do you really NEED super-accurate humidity readings ?
>>    For like a big commercial greenhouse, YES. For yer
>>    back-yard, close-enough may be close-enough.
>>
> Back when I was an student in the 80's, one mechanical engineering
> professor described doing wet/dry bulb measurements.  The thermometers
> were tied to lanyards, and you would whirl them around in the air at
> a certain rate to get more air flow over the bulbs during the
> measurement.  It increased the difference between the wet and dry
> readings for better accuracy, and the tables were adjusted for that
> affect.  My old thermodynamics textbook has a Psychrometric Chart in
> the back that you could use for calculating the absolute humidity from
> the temperatures.  It doesn't say whether the bulbs should be whirled
> around or not, maybe that was common knowledge back then.

   "Whirl-around" IS best.

   However, for a fixed unit these days, maybe the
   best is a tiny PI fan that sucks air over the
   thing. Start the fan like 60 seconds before you
   make the reading. Doesn't need MUCH power.

   Anyway, kind-of EXACT humidity readings are a sort
   of black art. A number of cheepo approaches, some
   small and low $$$, but expect at least a 15% variance
   from reality.

   I did lots of environmental field units, tried a
   bunch of 'solutions'. None of the 'cheap' ones were
   very good - though kinda sorta "good enough". The
   one diff was for a commercial greenhouse, good yield
   required precise monitoring. Just for humidity I had
   to use a $250 unit to get 'precise'. They DID pay,
   but didn't LIKE it. Faked a wet/dry unit on some
   field units I did later using dual 1-wire DS
   temperature sensors. Cheaper but still Good Enough.

   Greenhouse, if humidity too low, you sent pulses to
   a 'mist' unit - sprayed water mist into the air.
   Wait 30 minutes, test again.

[toc] | [prev] | [next] | [standalone]

#89501 — Re: WiFi range ...

On 03/08/2026 05:12, c186282 wrote:
> kind-of EXACT humidity readings are a sort
>    of black art.

The presence of a tree exuding transpired water can totally distort a 
reading
As cam a crowd of sweaty people

-- 
Ideas are more powerful than guns. We would not let our enemies have 
guns, why should we let them have ideas?

Josef Stalin

[toc] | [prev] | [next] | [standalone]

#89520 — Re: WiFi range ...

On 8/3/26 07:22, The Natural Philosopher wrote:
> On 03/08/2026 05:12, c186282 wrote:
>> kind-of EXACT humidity readings are a sort
>>    of black art.
> 
> The presence of a tree exuding transpired water can totally distort a 
> reading
> As cam a crowd of sweaty people

   Immediate environment is indeed a complicating factor !
   Similar issues with getting accurate temperatures. Sun
   hits a dark or concrete patch 50 yards away at a certain
   time of day and it may send a plume of hot air at yer
   device.

   As such, most such measurements are going to just be
   "(maybe) Good Enough".

   There are standards for professional instruments like
   the Weather Service might install at airports and such.
   A certain kind of housing, placement, height and such.
   That doesn't mean the readings are 100% accurate, just
   that they're done in a standard fashion that can more
   or less be compared to similar installations.

   I've used the olde-tyme mechanical drum recorders. It's
   amazing how much "jitter" you could outright SEE on the
   paper. Even opening the instrument box caused the figures
   to jit up or down a little right before your eyes. Means
   "accuracy" here is always a somewhat soft figure.

   Did a one-off climate gadget for a pro greenhouse once.
   They had data saying the crop qual would be best at a
   very specific temperature and humidity. Spent something
   near $400 (mid 80s dollars) on something that'd be
   accurate enough to make them happy. It was a wet/dry
   system (thermocouples I think but can't remember) and had
   a little fan to suck air past the sensors. You had to
   re-fill it with water every so many days. Used an 8051 uC
   for recording AND actuating 'mist' squirters (just a
   solenoid). The clients sold to the 'elite organic vegan'
   crowd and could get top dollar for like mini tomatoes
   and weird salad green shit I'd never eat. Pretty simple
   programming with just a little IQ added to note the
   RATE of humidity change and react accordingly.

   Anyway, a home-grown wet/dry setup is very easy to
   realize using ds18b20s and something even as small
   as a Uno or Pi0. Adafruit(?) does or did sell a
   tiny uC unit (ard compat) with a couple of A/D pins
   and I think I2C and/or 1-wire connections. "Trinket" ?
   Bought one long back but never got around to using it.
   Really small and low power though.

[toc] | [prev] | [next] | [standalone]

#89549 — Re: WiFi range ...

On 04/08/2026 01:20, c186282 wrote:
> On 8/3/26 07:22, The Natural Philosopher wrote:
>> On 03/08/2026 05:12, c186282 wrote:
>>> kind-of EXACT humidity readings are a sort
>>>    of black art.
>>
>> The presence of a tree exuding transpired water can totally distort a 
>> reading
>> As cam a crowd of sweaty people
> 
>    Immediate environment is indeed a complicating factor !
>    Similar issues with getting accurate temperatures. Sun
>    hits a dark or concrete patch 50 yards away at a certain
>    time of day and it may send a plume of hot air at yer
>    device.
> 
My oil tank monitor regularly shows temps over 40°C in its black case 
with the sun shining on it

>    As such, most such measurements are going to just be
>    "(maybe) Good Enough".
> 
>    There are standards for professional instruments like
>    the Weather Service might install at airports and such.
>    A certain kind of housing, placement, height and such.
>    That doesn't mean the readings are 100% accurate, just
>    that they're done in a standard fashion that can more
>    or less be compared to similar installations.
> 
Yes.
The whole concept of 'global average temperature' falls apart when you 
realise most of it is interpolated from stations thousands of miles 
apart mounted in less than ideal positions.

>    I've used the olde-tyme mechanical drum recorders. It's
>    amazing how much "jitter" you could outright SEE on the
>    paper. Even opening the instrument box caused the figures
>    to jit up or down a little right before your eyes. Means
>    "accuracy" here is always a somewhat soft figure.
> 
Agreed

>    Did a one-off climate gadget for a pro greenhouse once.
>    They had data saying the crop qual would be best at a
>    very specific temperature and humidity. Spent something
>    near $400 (mid 80s dollars) on something that'd be
>    accurate enough to make them happy. It was a wet/dry
>    system (thermocouples I think but can't remember) and had
>    a little fan to suck air past the sensors. You had to
>    re-fill it with water every so many days. Used an 8051 uC
>    for recording AND actuating 'mist' squirters (just a
>    solenoid). The clients sold to the 'elite organic vegan'
>    crowd and could get top dollar for like mini tomatoes
>    and weird salad green shit I'd never eat. Pretty simple
>    programming with just a little IQ added to note the
>    RATE of humidity change and react accordingly.
> 
Nice fun bit of coding

>    Anyway, a home-grown wet/dry setup is very easy to
>    realize using ds18b20s and something even as small
>    as a Uno or Pi0. Adafruit(?) does or did sell a
>    tiny uC unit (ard compat) with a couple of A/D pins
>    and I think I2C and/or 1-wire connections. "Trinket" ?
>    Bought one long back but never got around to using it.
>    Really small and low power though.
> 
I've just used TMP36s on the PCB coupled to a PICO Ws ADC. If the Pi 
pico W is permanently powered up I subtract  four degrees to compensate 
for onboard heating

In practice it seems good to about half a degree °C

But as you say, issues can be summarised into two camps

1. How accurate is your equipment?
2. How representative is it's siting of the environment you want to monitor?

I may do something with humidity too. Experience suggest you need about 
1°C extra heating for every 10% reduction of in-house humidity.


-- 
“There are two ways to be fooled. One is to believe what isn’t true; the 
other is to refuse to believe what is true.”

—Soren Kierkegaard

[toc] | [prev] | [next] | [standalone]

#89571 — Re: WiFi range ...

On 8/4/26 06:37, The Natural Philosopher wrote:
> On 04/08/2026 01:20, c186282 wrote:
>> On 8/3/26 07:22, The Natural Philosopher wrote:
>>> On 03/08/2026 05:12, c186282 wrote:
>>>> kind-of EXACT humidity readings are a sort
>>>>    of black art.
>>>
>>> The presence of a tree exuding transpired water can totally distort a 
>>> reading
>>> As cam a crowd of sweaty people
>>
>>    Immediate environment is indeed a complicating factor !
>>    Similar issues with getting accurate temperatures. Sun
>>    hits a dark or concrete patch 50 yards away at a certain
>>    time of day and it may send a plume of hot air at yer
>>    device.
>>
> My oil tank monitor regularly shows temps over 40°C in its black case 
> with the sun shining on it

   Never had to monitor an "oil tank".

   But, if exposed to sun/wind/etc, your ARE gonna
   get weird figures all day.

   As said, Temp/Humidity is a ROUGH figure always.
   Never try to get TOO technical on those figures.

>>    As such, most such measurements are going to just be
>>    "(maybe) Good Enough".
>>
>>    There are standards for professional instruments like
>>    the Weather Service might install at airports and such.
>>    A certain kind of housing, placement, height and such.
>>    That doesn't mean the readings are 100% accurate, just
>>    that they're done in a standard fashion that can more
>>    or less be compared to similar installations.
>>
> Yes.
> The whole concept of 'global average temperature' falls apart when you 
> realise most of it is interpolated from stations thousands of miles 
> apart mounted in less than ideal positions.

   This "science" falls apart once you pay even the
   slightest attention.

   WHAT the fuck is going on - today or this year - is
   always kind of a mystery. Butterflies and more
   butterflies .........

>>    I've used the olde-tyme mechanical drum recorders. It's
>>    amazing how much "jitter" you could outright SEE on the
>>    paper. Even opening the instrument box caused the figures
>>    to jit up or down a little right before your eyes. Means
>>    "accuracy" here is always a somewhat soft figure.
>>
> Agreed

   From those devices - hell YES. Even tiny shit
   would, visibly, influence the figures.

>>    Did a one-off climate gadget for a pro greenhouse once.
>>    They had data saying the crop qual would be best at a
>>    very specific temperature and humidity. Spent something
>>    near $400 (mid 80s dollars) on something that'd be
>>    accurate enough to make them happy. It was a wet/dry
>>    system (thermocouples I think but can't remember) and had
>>    a little fan to suck air past the sensors. You had to
>>    re-fill it with water every so many days. Used an 8051 uC
>>    for recording AND actuating 'mist' squirters (just a
>>    solenoid). The clients sold to the 'elite organic vegan'
>>    crowd and could get top dollar for like mini tomatoes
>>    and weird salad green shit I'd never eat. Pretty simple
>>    programming with just a little IQ added to note the
>>    RATE of humidity change and react accordingly.
>>
> Nice fun bit of coding

   Really wasn't difficult at all. Close to 'fuzzy logic'.
   Easy to do with even a '51 so long as you boosted vals
   to integers.

   Did have a big tome on fuzzy logic - dumped it when
   I retired. It DOES have its practical uses though.
   Adds some crude "AI" to things with minimal CPU
   consumption.

>>    Anyway, a home-grown wet/dry setup is very easy to
>>    realize using ds18b20s and something even as small
>>    as a Uno or Pi0. Adafruit(?) does or did sell a
>>    tiny uC unit (ard compat) with a couple of A/D pins
>>    and I think I2C and/or 1-wire connections. "Trinket" ?
>>    Bought one long back but never got around to using it.
>>    Really small and low power though.
>>
> I've just used TMP36s on the PCB coupled to a PICO Ws ADC. If the Pi 
> pico W is permanently powered up I subtract  four degrees to compensate 
> for onboard heating

   PICOs seem pretty good - although the instructions
   on-line seem WAY too complicated. Pref'ed PICS back
   in the day. A little ASM mixed with 'C' and ....

   Do HAVE a PICO ... haven't yet found a use for it.
   Will eventually.

   I'm gonna still boost the Ard Uno for 'small' stuff.
   Massively supported, a lib for EVERYTHING. Cheap,
   simple, easy to program. Even has low-power libs
   that can put it to sleep between Needs - making
   solar-powered apps work good.

> In practice it seems good to about half a degree °C

   The 18b20 ??? It IS pretty damned good - and,
   with one-wire libs, easy to deal with. Used a
   lot of them with uC's, Ards, and lower-end PIs.

   More than "good enough".

   LAST one I did, for a Pi3, monitored temps in
   the "server room". Worked great. Little client/
   server app (python) to deliver the info. The
   "server room" was an old CLOSET ... an A/C vent
   was added but it STILL kinda ran hot. Six
   'servers' in there.

> But as you say, issues can be summarised into two camps
> 
> 1. How accurate is your equipment?
> 2. How representative is it's siting of the environment you want to 
> monitor?

   Don't forget "How Accurate Do You REALLY Need".

   Temp/H ... always kinda "fuzzy".

> I may do something with humidity too. Experience suggest you need about 
> 1°C extra heating for every 10% reduction of in-house humidity.

   If you WANT ... I'd suggest the little box with two
   18b20s - one set with a "wet bulb" ... and a tiny PI
   fan that sucks air over the sensors. This is CHEAP
   and EASY - you can fab something from junk easily
   in an afternoon.

   One of those 'travel-sized' Tylenol plastic
   bottles are good for yer wet-bulb. Arid
   climate, refill once a week. Humid climates
   you might get by longer.

   Time ... start fan 30 secs early. Take readings.
   Turn off fan. 5/10/30 minutes later, repeat.

   PICs ... long back MicroChip sold a nice all-purpose
   serial programmer box. Fit anything from 12xxx to
   all the other 8/16 chips. Great. THEN they Went
   Bad ... NOW expensive "ICE" units and you have
   to buy pretty dedicated adapters for almost EVERY
   kind of chip. A horrible rip-off. USED to use a
   lot of PICs - you could even use them to emulate
   'smart' 4000 series logic chips if you didn't need
   hyper speed - CHEAPER than many 4000 series. Have
   not used them for a good decade now ... they just
   made it too expensive/complex.

   Idiots.

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#89599 — Re: WiFi range ...

On 05/08/2026 06:52, c186282 wrote:
> On 8/4/26 06:37, The Natural Philosopher wrote:
>> On 04/08/2026 01:20, c186282 wrote:
>>> On 8/3/26 07:22, The Natural Philosopher wrote:
>>>> On 03/08/2026 05:12, c186282 wrote:
>>>>> kind-of EXACT humidity readings are a sort
>>>>>    of black art.
>>>>
>>>> The presence of a tree exuding transpired water can totally distort 
>>>> a reading
>>>> As cam a crowd of sweaty people
>>>
>>>    Immediate environment is indeed a complicating factor !
>>>    Similar issues with getting accurate temperatures. Sun
>>>    hits a dark or concrete patch 50 yards away at a certain
>>>    time of day and it may send a plume of hot air at yer
>>>    device.
>>>
>> My oil tank monitor regularly shows temps over 40°C in its black case 
>> with the sun shining on it
> 
>    Never had to monitor an "oil tank".
> 
>    But, if exposed to sun/wind/etc, your ARE gonna
>    get weird figures all day.
> 
The ultrasonics delay that measures oil level changes with tempertaure 
as does the depth of the oil due to expansion., I WANT to know how hot 
the tank is.

>    As said, Temp/Humidity is a ROUGH figure always.
>    Never try to get TOO technical on those figures.
> 
>>>    As such, most such measurements are going to just be
>>>    "(maybe) Good Enough".
>>>
>>>    There are standards for professional instruments like
>>>    the Weather Service might install at airports and such.
>>>    A certain kind of housing, placement, height and such.
>>>    That doesn't mean the readings are 100% accurate, just
>>>    that they're done in a standard fashion that can more
>>>    or less be compared to similar installations.
>>>
>> Yes.
>> The whole concept of 'global average temperature' falls apart when you 
>> realise most of it is interpolated from stations thousands of miles 
>> apart mounted in less than ideal positions.
> 
>    This "science" falls apart once you pay even the
>    slightest attention.
> 
Certainly to the depth of precision and alarm its stated with.


>    WHAT the fuck is going on - today or this year - is
>    always kind of a mystery. Butterflies and more
>    butterflies .........
> 
Less butterflies bees and all sorts of insects year upon year. Just 
infestations of ladybirds, fruit flies and house flies.

>>>    I've used the olde-tyme mechanical drum recorders. It's
>>>    amazing how much "jitter" you could outright SEE on the
>>>    paper. Even opening the instrument box caused the figures
>>>    to jit up or down a little right before your eyes. Means
>>>    "accuracy" here is always a somewhat soft figure.
>>>
>> Agreed
> 
>    From those devices - hell YES. Even tiny shit
>    would, visibly, influence the figures.
> 
I always laugh at the people who say 'solar panels work under cloud'.
Some of us did photography and tow stops in cloud or near sunset - 4 
times less light - was the order of the day.

Its all part of the Liberal non scientific brain that doesn't do math, 
quantitiy or any kind of gradation. It's all black and white.

V8 bad. Solar panel Good


>>>    Did a one-off climate gadget for a pro greenhouse once.
>>>    They had data saying the crop qual would be best at a
>>>    very specific temperature and humidity. Spent something
>>>    near $400 (mid 80s dollars) on something that'd be
>>>    accurate enough to make them happy. It was a wet/dry
>>>    system (thermocouples I think but can't remember) and had
>>>    a little fan to suck air past the sensors. You had to
>>>    re-fill it with water every so many days. Used an 8051 uC
>>>    for recording AND actuating 'mist' squirters (just a
>>>    solenoid). The clients sold to the 'elite organic vegan'
>>>    crowd and could get top dollar for like mini tomatoes
>>>    and weird salad green shit I'd never eat. Pretty simple
>>>    programming with just a little IQ added to note the
>>>    RATE of humidity change and react accordingly.
>>>
>> Nice fun bit of coding
> 
>    Really wasn't difficult at all. Close to 'fuzzy logic'.
>    Easy to do with even a '51 so long as you boosted vals
>    to integers.
> 
>    Did have a big tome on fuzzy logic - dumped it when
>    I retired. It DOES have its practical uses though.
>    Adds some crude "AI" to things with minimal CPU
>    consumption.
Yes.

> 
>>>    Anyway, a home-grown wet/dry setup is very easy to
>>>    realize using ds18b20s and something even as small
>>>    as a Uno or Pi0. Adafruit(?) does or did sell a
>>>    tiny uC unit (ard compat) with a couple of A/D pins
>>>    and I think I2C and/or 1-wire connections. "Trinket" ?
>>>    Bought one long back but never got around to using it.
>>>    Really small and low power though.
>>>
>> I've just used TMP36s on the PCB coupled to a PICO Ws ADC. If the Pi 
>> pico W is permanently powered up I subtract  four degrees to 
>> compensate for onboard heating
> 
>    PICOs seem pretty good - although the instructions
>    on-line seem WAY too complicated. Pref'ed PICS back
>    in the day. A little ASM mixed with 'C' and ....
> 
>    Do HAVE a PICO ... haven't yet found a use for it.
>    Will eventually.
> 
I found more trouble in setting up the development enviroment (C SDK) 
than in coding the little buggers

Although some of the networking libraries are rdacically non Unix in 
their layout


>    I'm gonna still boost the Ard Uno for 'small' stuff.
>    Massively supported, a lib for EVERYTHING. Cheap,
>    simple, easy to program. Even has low-power libs
>    that can put it to sleep between Needs - making
>    solar-powered apps work good.
> 
>> In practice it seems good to about half a degree °C
> 
>    The 18b20 ??? It IS pretty damned good - and,
>    with one-wire libs, easy to deal with. Used a
>    lot of them with uC's, Ards, and lower-end PIs.
> 
No. The TMP36.
>    More than "good enough".
> 
>    LAST one I did, for a Pi3, monitored temps in
>    the "server room". Worked great. Little client/
>    server app (python) to deliver the info. The
>    "server room" was an old CLOSET ... an A/C vent
>    was added but it STILL kinda ran hot. Six
>    'servers' in there.
> 
>> But as you say, issues can be summarised into two camps
>>
>> 1. How accurate is your equipment?
>> 2. How representative is it's siting of the environment you want to 
>> monitor?
> 
>    Don't forget "How Accurate Do You REALLY Need".
> 
>    Temp/H ... always kinda "fuzzy".
> 
>> I may do something with humidity too. Experience suggest you need 
>> about 1°C extra heating for every 10% reduction of in-house humidity.
> 
>    If you WANT ... I'd suggest the little box with two
>    18b20s - one set with a "wet bulb" ... and a tiny PI
>    fan that sucks air over the sensors. This is CHEAP
>    and EASY - you can fab something from junk easily
>    in an afternoon.
> 
Nah. I'll juts buy one of those modules that do it all with resistance 
or capacitance

>    One of those 'travel-sized' Tylenol plastic
>    bottles are good for yer wet-bulb. Arid
>    climate, refill once a week. Humid climates
>    you might get by longer.
> 
>    Time ... start fan 30 secs early. Take readings.
>    Turn off fan. 5/10/30 minutes later, repeat.
> 
>    PICs ... long back MicroChip sold a nice all-purpose
>    serial programmer box. Fit anything from 12xxx to
>    all the other 8/16 chips. Great. THEN they Went
>    Bad ... NOW expensive "ICE" units and you have
>    to buy pretty dedicated adapters for almost EVERY
>    kind of chip. A horrible rip-off. USED to use a
>    lot of PICs - you could even use them to emulate
>    'smart' 4000 series logic chips if you didn't need
>    hyper speed - CHEAPER than many 4000 series. Have
>    not used them for a good decade now ... they just
>    made it too expensive/complex.
> 
>    Idiots.
> 
The model of simply downloading a file over USB to code the Picos is 
nice and simple.

-- 
In theory, there is no difference between theory and practice.
In practice, there is.
-- Yogi Berra

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#89624 — Re: WiFi range ...

On 8/5/26 08:21, The Natural Philosopher wrote:
> On 05/08/2026 06:52, c186282 wrote:
>> On 8/4/26 06:37, The Natural Philosopher wrote:
>>> On 04/08/2026 01:20, c186282 wrote:
>>>> On 8/3/26 07:22, The Natural Philosopher wrote:
>>>>> On 03/08/2026 05:12, c186282 wrote:
>>>>>> kind-of EXACT humidity readings are a sort
>>>>>>    of black art.
>>>>>
>>>>> The presence of a tree exuding transpired water can totally distort 
>>>>> a reading
>>>>> As cam a crowd of sweaty people
>>>>
>>>>    Immediate environment is indeed a complicating factor !
>>>>    Similar issues with getting accurate temperatures. Sun
>>>>    hits a dark or concrete patch 50 yards away at a certain
>>>>    time of day and it may send a plume of hot air at yer
>>>>    device.
>>>>
>>> My oil tank monitor regularly shows temps over 40°C in its black case 
>>> with the sun shining on it
>>
>>    Never had to monitor an "oil tank".
>>
>>    But, if exposed to sun/wind/etc, your ARE gonna
>>    get weird figures all day.
>>
> The ultrasonics delay that measures oil level changes with tempertaure 
> as does the depth of the oil due to expansion., I WANT to know how hot 
> the tank is.

   DID use a bunch of ultrasonic sensors for field projects.
   NOT as straight up as promised ... every time you start
   them they kinda establish a new 'zero'. Had to write
   something that'd start them like five times ... then do
   a stat approach to seven readings thereafter. THEN the
   numbers were really damned good. Only took like five
   or six seconds. Bonus - it disappeared rain/ripple
   effects.


>>
> The model of simply downloading a file over USB to code the Picos is 
> nice and simple.

   Yea, they ARE 'better' these days.

   But I'm still pissed that MicroChip and
   friends let it get SO much more complex
   and expensive ! They kind of cut their
   own throats.

   Little uCs ... GREAT devices IF you can
   deal with them easily. Found SO many uses
   for them in the past. NOW won't touch them.

   Last "field environ units" I built used a
   PIC 16 and 12 ... didn't even have to think
   about using them, replaced several 4000/7000
   chips and you could TWEAK them easily.

   I like the Ard Uno boards with the socketed
   processor chips. The board is both yer
   programmer AND test unit. Then pull the chip
   and solder it into yer whatever. All CHEAP
   and EASY.

   Sometimes "high-speed" isn't required for
   some I/O situations.

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#89637 — Re: WiFi range ...

On 06/08/2026 07:47, c186282 wrote:
> But I'm still pissed that MicroChip and
>    friends let it get SO much more complex
>    and expensive ! They kind of cut their
>    own throats.
> 
I bough ten 2040 based modules fro alixepress for about $10

Essentially pi Pico with no wireless and less pins

https://www.aliexpress.com/item/1005006024307280.html

>    Little uCs ... GREAT devices IF you can
>    deal with them easily. Found SO many uses
>    for them in the past. NOW won't touch them.

Use em a lot

-- 
The lifetime of any political organisation is about three years before 
its been subverted by the people it tried to warn you about.

Anon.

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#89650 — Re: WiFi range ...

On Thu, 6 Aug 2026 13:01:13 +0100, The Natural Philosopher wrote:

> I bough ten 2040 based modules fro alixepress for about $10
> 
> Essentially pi Pico with no wireless and less pins
> 
> https://www.aliexpress.com/item/1005006024307280.html

They're about $10 apiece on Amazon. AliExpress go hit by the US de minimis 
ruling. Even before that I didn't use them. I briefly sniffed at STM32 and 
many people reported AliExpress 'Black Pill' boards definitely were black 
pills. 

Not boards, but I'd ordered Photon Micro Lights from Amazon. Some were 
very crude Chinese knockoffs. Even the Phillip screw heads looked like 
they'd been chewed in by a gerbil. When I contacted Amazon they reversed 
the charges and said to not bother returning the product. That vendor 
vanished. I imaging AliExpress's response would be 'Not our problem.'

It has been a mystery to me. China can obviously do excellent work but 
some Chinese knockoffs have the appearance of the product they are 
imitating but are crap. At what point does the manufacturing cost of crap 
versus doing a little better job make sense? 

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#89665 — Re: WiFi range ...

On 06/08/2026 20:56, rbowman wrote:
> t has been a mystery to me. China can obviously do excellent work but
> some Chinese knockoffs have the appearance of the product they are
> imitating but are crap. At what point does the manufacturing cost of crap
> versus doing a little better job make sense?

A great deal of chinas 'exports' are only done to gain subsidies. China 
wants Western currencies at any price and so shipping any old tat - 
generally reject items form the 'failed test' bin - will net you a little.

Same thing happened in the EU. Many countries subsidies various exports. 
In Ireland  you drove your cows across the border to the North, 
technically part of the UK, and collected an EU export subsidy. Then you 
drove them back through your neighbours farm that straddled the border 
the following night.

I think the best one was the Spanish solar farm collecting subsidies for 
generation *at night*.

They were using Diesel generators. Diesel cost a lot less than they were 
paid for 'green electricity'...


-- 
Ideas are more powerful than guns. We would not let our enemies have 
guns, why should we let them have ideas?

Josef Stalin

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#89676 — Re: WiFi range ...

On Thu, 6 Aug 2026 22:15:20 +0100, The Natural Philosopher wrote:

> Same thing happened in the EU. Many countries subsidies various exports.
> In Ireland  you drove your cows across the border to the North,
> technically part of the UK, and collected an EU export subsidy. Then you
> drove them back through your neighbours farm that straddled the border
> the following night.

I don't know if a subsidy is involved but I often buy Kerrygold or 
Dubliner cheese. It's excellent and very competitively priced compared to 
domestic brands like Tillamook. I don't use much butter but what I have is 
Kerrygold. They're brands of the Ornua dairy co-operative in Dublin.

Does Northern Ireland still have that strange status in the EU? I remember 
the discussions about the problems if there was a border with the Republic 
but haven't kept up.

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#89690 — Re: WiFi range ...

On 07/08/2026 04:41, rbowman wrote:
> On Thu, 6 Aug 2026 22:15:20 +0100, The Natural Philosopher wrote:
> 
>> Same thing happened in the EU. Many countries subsidies various exports.
>> In Ireland  you drove your cows across the border to the North,
>> technically part of the UK, and collected an EU export subsidy. Then you
>> drove them back through your neighbours farm that straddled the border
>> the following night.
> 
> I don't know if a subsidy is involved but I often buy Kerrygold or
> Dubliner cheese. It's excellent and very competitively priced compared to
> domestic brands like Tillamook. I don't use much butter but what I have is
> Kerrygold. They're brands of the Ornua dairy co-operative in Dublin.
> 
Kerrygold is nice butter.

I buy supermarket own brand which is probably Kerrygold in a plain wrapper.

Cheese? Ireland nothing special, rest of EU infinitely better - so many 
types available.

It's the one thing I do buy from the EU, that and some wines, although 
it's just as likely to S American,  S African, Australian or New  Zealand.

Or even middle eastern - had Lebanese wine once. Not bad.


> Does Northern Ireland still have that strange status in the EU? I remember
> the discussions about the problems if there was a border with the Republic
> but haven't kept up.

Yes. It is still being used as a lever to 'control the UK' . E.g. we are 
not allowed to zero rate VAT on domestic fuel because that would break 
the agreement in N Ireland as peole would buy heating oil in the North 
and drive it to the South, and with 'no borders' no one would stop them.

Most UK political class never wanted to leave the EU.  They love all the 
bureaucracy and the freedom from prosecution and the corruption.

WE are still fighting

-- 
"An intellectual is a person knowledgeable in one field who speaks out 
only in others...”

Tom Wolfe

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#89649 — Re: WiFi range ...

On Thu, 6 Aug 2026 02:47:37 -0400, c186282 wrote:

>    I like the Ard Uno boards with the socketed processor chips. The
>    board is both yer programmer AND test unit. Then pull the chip and
>    solder it into yer whatever. All CHEAP and EASY.

I have some AVR chips and a STK500 development board from before MicroChip 
bought Atmel.

https://www.manuallib.com/download//ATMEL-R-STK500-STARTER-KIT-AND-
DEVELOPMENT-SYSTEM-MANUAL.PDF

I should see if I can get it going with the current Microchip Studio or 
whatever they call the current IDE. First step would be a USB/RS232 
dongle.

https://wiki.seeedstudio.com/Atmel_AVRISP_STK500_USB_ISP_Programmer/

I'm not sure how this fits in. The only example I've seen uses the Uno 
pins to reprogram the boot loader. You would have to build your own board 
to replicate the original starter kit.

While the BASIC Stamp, PICAXE, and other devices existed the Arduino made 
life much easier. You could say it was something like installing MX or 
trying to get a functioning system with Linux From Scratch. 

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#87325

c186282 wrote:

> rbowman wrote:
> >> c186282 wrote:
>>
>>> I may have a use for RF "modems",
>>> a link to a kind of far-off property site. Do not need video, MAYbe the
>>> odd still image. The low speed isn't relevant, just the range. WiFi
>>> isn't gonna cut it at all.
>>
>> How far off? 
> 
>    About 1000 meters.
>    NO power utilities there.
Maybe look at specialised WiFi?  802.11ah HaLow

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#87326

>On Mon, 1 Jun 2026 08:10:41 +0100, Andy Burns <usenet@andyburns.uk> wrote:
>c186282 wrote:
>
>> rbowman wrote:
>> >> c186282 wrote:
>>>
>>>> I may have a use for RF "modems",
>>>> a link to a kind of far-off property site. Do not need video, MAYbe the
>>>> odd still image. The low speed isn't relevant, just the range. WiFi
>>>> isn't gonna cut it at all.
>>>
>>> How far off?
>>
>>    About 1000 meters.
>>    NO power utilities there.
>Maybe look at specialised WiFi?  802.11ah HaLow

For 1000 m and no mains, I would split the question into "link budget" and
"power budget" before buying anything.

If there is clean line of sight, a pair of outdoor point-to-point CPE radios
(Ubiquiti/MikroTik/TP-Link CPE type kit) is usually simpler than old-style RF
modems and can be throttled down to very little traffic.  The catch is that the
remote end still needs a small panel, battery, charge controller and a
weatherproof enclosure, so idle power matters more than peak throughput.

If it is not line-of-sight, or if the remote end is just sending occasional
sensor data/status and maybe not images, then LoRa/LoRaWAN-type gear is worth a
look.  It is much easier to run from a small battery/solar setup, but it is not
a substitute for an IP-ish link with images.

HaLow sits between those worlds.  I would check local regulatory limits and the
actual antenna options before assuming it beats a boring directional 2.4/5 GHz
bridge at only 1 km.

-- 
TheLastSysop <thelastsysop@dev.null>
"I survived the great rm -rf / rehearsal and all I got was this .signature."

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#87353

On 6/1/26 03:33, TheLastSysop wrote:
>> On Mon, 1 Jun 2026 08:10:41 +0100, Andy Burns <usenet@andyburns.uk> wrote:
>> c186282 wrote:
>>
>>> rbowman wrote:
>>>>> c186282 wrote:
>>>>
>>>>> I may have a use for RF "modems",
>>>>> a link to a kind of far-off property site. Do not need video, MAYbe the
>>>>> odd still image. The low speed isn't relevant, just the range. WiFi
>>>>> isn't gonna cut it at all.
>>>>
>>>> How far off?
>>>
>>>     About 1000 meters.
>>>     NO power utilities there.
>> Maybe look at specialised WiFi?  802.11ah HaLow
> 
> For 1000 m and no mains, I would split the question into "link budget" and
> "power budget" before buying anything.

   The LINKS - several variants - seem to be affordable.
   At 400/900mhz seem to have good range and obstacle
   immunity.

   The power budget - always a tricky equation. Plenty
   of lithium chargers that plug into PV panels. The
   "Seeed" brand, "LiPo Rider Plus", are the best - no
   voltage spikes even at low/no demand.

   My old dataloggers could get by on a 5w panel just
   fine. However they didn't xmit anything, just
   recorded to a card. Came out of sleep every 15
   minutes.

   However transmitting can use up a lot more power.
   Anything 'on demand' like a camera frame will
   use up more, transiently.

> If there is clean line of sight, a pair of outdoor point-to-point CPE radios
> (Ubiquiti/MikroTik/TP-Link CPE type kit) is usually simpler than old-style RF
> modems and can be throttled down to very little traffic.  The catch is that the
> remote end still needs a small panel, battery, charge controller and a
> weatherproof enclosure, so idle power matters more than peak throughput.

   My line-of-sight is NOT "clean" ... ergo the interest
   in lower-freq links.

> If it is not line-of-sight, or if the remote end is just sending occasional
> sensor data/status and maybe not images, then LoRa/LoRaWAN-type gear is worth a
> look.  It is much easier to run from a small battery/solar setup, but it is not
> a substitute for an IP-ish link with images.
> 
> HaLow sits between those worlds.  I would check local regulatory limits and the
> actual antenna options before assuming it beats a boring directional 2.4/5 GHz
> bridge at only 1 km.

   Still looking in to What's Out There these days.
   A few possibly good options - also a few that,
   on consideration, probably won't cut it.

   Gotta run a few numbers yet, then I'll decide.

   PIs are OUT ... massive power hogs. Good
   microcontrollers give much more control.

   Anyway, fun project ! Tired of not knowing
   what's going on at my other property too.
   If it's on fire I wanna know. If squats
   set up a camp, I wanna know. If shits are
   dumping trash, I wanna know.

   I know a guy with a bucket-truck - for a few
   bucks he could screw an instrument package to
   one of the tall trees. Olive-drab canvas
   strips with an odd splurt of 'primer' brown
   and it'd look perfectly natural unless you
   actually climbed the tree. The panel can go
   on top, angled up maybe 40 degrees, kind of
   invisible. Have had to use 'disguise' before
   in semi-public areas.

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#87352

On 6/1/26 03:10, Andy Burns wrote:
> c186282 wrote:
> 
>> rbowman wrote:
>> >> c186282 wrote:
>>>
>>>> I may have a use for RF "modems",
>>>> a link to a kind of far-off property site. Do not need video, MAYbe the
>>>> odd still image. The low speed isn't relevant, just the range. WiFi
>>>> isn't gonna cut it at all.
>>>
>>> How far off? 
>>
>>    About 1000 meters.
>>    NO power utilities there.
> Maybe look at specialised WiFi?  802.11ah HaLow

   "Lo-RA" ? That's been recommended for the described
   range and need. Am looking into it.

   A few other suggestions too. 900mhz band may be
   the 'best' - less speed but more range and more
   immunity to common obstacles. Old days (and a
   few are still sold) 400mhz might also meet my
   modest needs with even better obstacle immunity.
   Clearly "live audio", which would be a NICE
   option, is gonna be just too much bandwidth.
   Can live without that.

   Anyway, need a few little weather sensors and
   the ability to request video FRAMES on demand.
   That's kinda do-able at about a mile's range
   without licenses or such govt BS. It has to run
   on maybe a 10-20w solar panel (easy to hide).
   Don't need constant data, just kinda "on demand".

   I've done multi-sensor dataloggers before, know
   how to code it, wire 'em down to the chips etc.
   Made a dozen based on the Ard 2560 - good
   'sleep'/low-power lib. They didn't xmit though,
   just saved to an SD card. Worked for many years.
   Got by on just a 5w panel.

   Somebody here said their company/group made
   really good 802.11 RF links - but did not
   name the maker.

   Long back such devices didn't even pretend to be
   network connections - just serial modems. That
   worked and was less complicated. Linux still has
   all the needed utils to cope with serial comms.

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#87355

On 2026-06-01 22:15, c186282 wrote:
>    Somebody here said their company/group made
>    really good 802.11 RF links - but did not
>    name the maker.

You would not want to buy ours. For starters, we'd charge
you about $3K per node. And we are planning to close the business in a year.

-- 
Lars Poulsen - an old geek in Santa Barbara, California

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#87359

On 6/2/26 01:50, Lars Poulsen wrote:
> On 2026-06-01 22:15, c186282 wrote:
>>    Somebody here said their company/group made
>>    really good 802.11 RF links - but did not
>>    name the maker.
> 
> You would not want to buy ours. For starters, we'd charge
> you about $3K per node. And we are planning to close the business in a 
> year.

   At $3k I can see why :-)

   Another old govt/industrial "solution" idiots
   would vastly over-pay for ???

   There are MUCH cheaper LoRa and related to be
   found online these days.

   2.4 is too obstacle-sensitive for my need, but
   900/400 can work.

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